The present application claims the benefit of and priority to a pending provisional application entitled “Asynchronous Common Mode Noise Immune Galvanic Isolated Signal Level Shifting,” Ser. No. 61/675,932 filed on Jul. 26, 2012. The disclosure in this pending provisional application is hereby incorporated fully by reference into the present application.
Level shifters can be utilized to level shift a signal between circuits that are referenced to different grounds. One or more isolation barriers can provide galvanic isolation between the circuits. Exemplary approaches to galvanic isolation can be based on capacitance, induction, electromagnetic waves, optical, acoustic, and mechanical means to exchange energy between the circuits. In some applications, the level shifter may be in a power system or another noisy environment. For example, the signal may correspond to a control signal for a power switch of a switch mode power supply. In such systems, noise can interfere with the accuracy of the level shifter resulting in distortion. Distortion may not be tolerable in certain applications, such as audio systems where the distortion can increase total harmonic distortion resulting in reduced sound quality.